Service-meter apparatus and circuit for telephone-substations.



No. 648,805. Patented May 1, I900.

H. E. SHREEVE.

I SERVICE METER APPARATUS AND CIRCUIT FOR TELEPHONE SUBSTATIONS. (Application filed .Tan. 22, 1900. (No Model.)

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fittest, [amnion UNITED STATES PATENT OFFlCE.

IIERBER'. E. SIIREEVE, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO THE AMERICAN BELL TELEPHONE COMPANY, OF SAME PLACE.

SERYlCE-METER APPARATUS AND CIRCUIT FOR TELEPHONE-SUBSTATIONS.

SPECIFICATION forming part of Letters Patent No. 648,805, dated May 1, 1900. Application filed January 22, 1900. Serial No. 2.374. (No model.

To all whom it may concern.-

lie it known that I, HERBERT E. SHREEVE, residing at Boston, in' the county of Sufiolk and State of Massachusetts, have invented certain Improvements in Service-Meter Apparatus and Circuits for Telephone Substations, of which the following is a specification.

In order to relieve the operators at central stations of the necessity of recording calls originating onmeasured-service telephonelines, automatic recording apparatusknown as service-meters or call-registers, have been devised and applied, these meters being in some cases located at the central station, while in other cases they are placed at the substation.v 1 4 The service-meter concerned in my inven tion is intended for use at telephone-system substations and is adapted for application to telephone systems of the so-called commonbattery relay class. It is designed that the registration ofa call on the dial ofsucli a substation service-meter shall require the successive performance of two steps, one prodnzccgl by the act of a connection initiating su )scisber at such station in sending a call and the other by the act of the ceutralrstationv operator in answering such call. The call- .register or service-meter is actuated bya p0- larized elcctromagnet, the armature of which oscillates from one magnet-pole to the other, according to the direction of current circulating through the magnet-coils. \Vhen the telephone at a calling-substation is removed from the hook-switch, the circuit is closed by the action of the said switch and current of proper direction to produce a swing of the meterarmature flows through the circuit from the central-station battery, giving the call by causing a display at said central station of the regular line-signal and producing such a single movement of the meter-armature as is required for the first step toward the registration of the call by said meter. In response to the call-signal the operator inserts one switch-plugof a regularpair into an answering-jack or switch-socket ofv the station-meter, responding to the reversal or;

informed of the number of the desired connection the operator after testing the line of the substation wanted sends a ringing-current over such line and then connects the two 1 for conversation.

It is of course required that the charge for service shall be made against that station only which in each connection initiates'the call, and that no charge shall be registered upon the meter of the substation which is called for communication with such initiating party. Experience, however, has shown that the operation of the meter at thecalled substation, though undesired, is liable to occur if the telephone at such station is taken from its book before the bell there ceases to ring, and this comes about becaus e the resistance in the circuit is thereby greatly decreased, causing a ling device or appliance which while the a1 ternating ringing current is being transmitted shall act to produce in the circuit containing the register-magnet a series of rapidly-recu rri n-g interruptions. whereby such alternating current is prevented from exercising an operative magnetizing effect upon the said register or meter-magnet, but which during the passage of the steady current em; ployed for inward signaling or transmitter supply will maintain the continuity of the meter-magnet circuit unimpaired. A shuntcircuit containing a suitable resistance surrounds the service meter magnet and the means for producing the current interruptions therethrough. The said interruptions in this way are restricted to the service-meter magnet and do not allect the circuit atlarge,

so that the apparatus producing them, which' being adapted to permit the operation of the said register by means of currentsof the latter class and to prevent its operation by currents of the former class.

In the drawings which accompany and illustrate this specification, Figure l is a diagramof a substation telephone-circuit containing a preferred form oi": the invention; and Figs. 2 and. 3 show modifications of the service-metercontrolling device. j

L represents a telephone-oireuitextending between a substation X and the central station Y, and a I) are its constituent conductors. The circuit is provided at the substation with the standard or usual common battery outfit of telephonic apparatus and at the ccntralstation switchboard has switch sockets or jacks J, a cut-off relay R, a line or cali signal relay R and the lamp-signals, controlled thereby. Z is a switch cord-circuit, (a number ofsuch being of course assigned to each operator,) the same beingprovided with the connectingplugs l, the repeatingcoil I, the battery Q,- the disconnecting or supervisory signals S, the calling-generator M, and the ringing or calling key I), these instrumentalities being all arranged in the usual manner.

The circuit-comfluctor b after passing the contact '0 ol' the cut-off relay R continues through the line-relay R and-connects by cond uctors 17and 15 with one pole of the common battery Q, and terminates in the earth connection 10, thus furnishing a circuit for the incoming-call signal, which circuit is closed to produce the said signal when the subscriber removes his telephone from the switch. Underthcse col (lirions the direct-ion of the current is outward over conductor (1 To anand inward by way of conductor (L.

d1 swcrsuch an incoming-call signal, the answering-plug-P is inserted in one of the acks J.

The ring-conductor 6' of said plug will then engage with the longenjack-spring 20 of conductor a, and the tip'conducter 5, thereof Will 'tacts 5 and 6.

engage with the shorter jack-sprin g 21 of con- 'ductor b. At the same time the rear sleeveconductor 7 of the answering-plug registers with the test-ring 22 and closes a circuit of the battery through the cut-oif relay R by way of wire 15, lamp S wire 13, plug-sleeve 7, ring 22, wire 19, and relay R, and the said relay operating severs the normal'battery connection; but the battery hasalsoa con nection with the switoh-plug'main-line con- Contact 6 connects with that pole of said battery to which the normal battery-connection 17 is attached by way of winding 3 of the repeating coil, conductor 11, ringing-key contact 23, key-spring y, and con: doctor 2', while the plug-tip.5 connects with the opposite pole of said battery 'by way of winding 2 of the repeatin -coil, conductor 9, ringing-key contact-point 24, spring y, and conductor 8. Thus by the insertion .of the I switch-plug, though the original battery connection is taken 01?, anew one for. the substation-transmitter is supplied, the current in this case, however, being of reversed direction. 7

" B indicates the service-meter apparatus at the substation X. The registering mechanism K thereof is operated by an electromagnet 7c, made sluggish by having iron'cores small. in diameter and. incased in copper sheaths in a mannerwellnnderstood and having a centrallyrpivoted armature 'r,'carry-- ing an escapement adapted. to engage the teeth of the escape-wheel 's, and controlling thereby the operation of the clock mechanism K of the service-meter. The'electromagnet and its armature are polarized by the permanent magnet 10. v

It is notdeemed necessary to show or describe any specific form of meter mechanism, and such a one as is'disclosed by Letters Patent of the United States granted to Hammond V. Hayes and'Thomas 0. Wales, J r., September. 7, 1897, No.589,4.31, or, in fact, any form possessing similar characteristics, may conveniently be employed.

V indicates the controlling device or vibrator, whichby my'invention is associated with the service-meter to protect the same from u ndesired operative influences. It comprises an electromagnet C, with a pend ulous armaturn 2), hung upon and free to swing about a pivot, which may be arranged in any suitable bracket or in an extension of the upper magnet-pole, as shown, an insulated suspended arm 0, a contact-pointn, carried thereby, and a similar con tact point or piece n mounted on the free end'of the armature, the said points it and n being normally'in contact with one another. v

The electrical connections of the service meter and the controlling device, both in relation to themselves and to the main circuit,

are as follows: The electroniagnet C ofi-the g, and a second resistance-coil e shunts, the

cleetromagnc k of the meter and also the separable contacts not of the controlling device, the latter shunt-circuit being completed by a conductor 15, which connects the conductor q at the pointj with the armature p. The

apparatus as a whole, including the electromagnets of both appliances and their respective shunts, may be placed in the circuit?! eitherin series with the entire substation outfit or with the transmitter and inductioncoil only. The former arrangementis the one shown, and the said apparatus is intro- .duced into the main circuit between the points It and i. To a certain extent the presence in the talking-circuit of the said electroniaghet C offers impedance to the passage of the voice-currents; but this difficulty is minimined by providing it with the said resistancecoil gin shunt relation therewith, the said coil, as well as resistance e, being preferably in a well-known manner wound double to avoid-self-induction. Thus when the system is at rest, and also when a steady current is passing through the circuit, there are two distinct paths for the current between the said points It and t; Beginning at i gne of these isthrough the coils of the meter-magnet k and thence by wire m to the pendent arm 0 and by way of, the contacts 11 11 the armatu re p, c0nductor i, pointj, conductor q,'point f, and the shunted controlling-device magnet C, while the other leads through shunt resistance coil e, conductor q, and electromagnet O. The

latter, being permanently shunted by the resistance-coil g, is connected around magnet C between the points f and h. It will be seen that the clectromagnet C of the controlling device V, though shunted, is at all timesin-the circuit, while the meter-magnet is out of the circuit whenever the contact-points n and n are separated. The suspended arm o tends to follow the forward movements of the armature, but by reason of its inertia exercises this tendency but slowly, so that when sudden and recurring vibrations of the armature are produced, as is the case while magneto call-currents are being transmitted, the arm 0 does not follow the armature immediately, and under such conditions the circuit, through the contacts 11M, is for the instant necessarily broken. The resistance of the coil 0 maybe about fifty ohms, that of the coil 9 about one hundred ohms, while the resistances of the electromagnets I; and C maybe seventeen and twenty-two ohms, respective] y.

- closing of the circuit by the hook-switch d causes current to flow from the battery Q via conductors .15 and 17, line-signal relay R armature 'v of cut-oil? relay R, main conductor I), to the point i, thence through the meter and meter-controlling appl ances and the station instruments to main conductor a, and by way of the cut-out relay-armature 3 lever '50 to ground G and the other pole of the-battery. 0\. ing to the lesser resistance of the electromagnets it and C the main portion of the current flows that way instead of through the shunt-resistances e'and g. The currentthus established in the circuit vitalizescall-relay R which lights up the signallamp 8. of the meter, which, attracting the armature 7', causes the same to rock on its pivot'and to make the first of the two steps required for the registration of the call. Then the opcrator in response to displayot' signalS inserts plug P into-the switch socket or jaekJ of the line, its tip 5 makes contact with the lower spring 21, its front sleeve (S-contacts with the upper spring 20, and its rear sleeve contacts with the test-ring, as already described, and current from battery Q operates thecut-oiii relay R and opens the-main circuit, cutting off the normal hattery copnection. At the same time the transniitter supply-cru'rent flows from the battery over-the line in 'a di- It also excites the electromagnet 7." 1

rection opposite to that resulting from the normal connection, and in this instance also the electromagnet k of the meter influenced which, indeed, is disestablished but for a moment and under conditions which do not impair the perfect operation of the apparatus.

Thus far the substation-circuit L has been regarded as the call-initiating circuit and its operation has been considered from that point of view. It will now be regarded as the circuit of the'substation with which comm unication is desired. To connect the callingcircuit with the called circuit'after the usual busytest, the operator inserts the calling or companion plug '1 of the pair into the jackJ of the latter, its tip 5 contacting with the lower spring 21 and its front sleeve 6 with the'npper spring 20. The battery-currentpassing to the called circuit is of such direction as to retain the armature of the service-meter at the wanted station in its normal position, and therefore exercises no' cllect thereon. She then depresses the button of the ringingkey I), forcing the springs 3/ y" thereof away from their normal contacts into connection with the terminals of the central-station callimmediately follow, and it therefore separates from the arm and the circuit through the meter-magnet is momentarily broken. 'W'hen the impulse or wave subsides, the armature p is released and drops back into contact with the arm, whichhas meanwhile swung toward the electromagnet 0,-and upon the riod of contact is very brief; but while it lasts current may flow through the coils of the me-. The said magnet, however, by

ter-magnet 7:. reason of the combined effect of its sluggishness and the brevity of the contact, does not become appreciably excited, such impulses as stalled and prevented.

reach it while theriuging-current is being transmitted over the line being too transient to reach their full value in the coils of such a slow-working magnet, and all undesirable, undcsigned, and accidental operation of the service-meter of the called line under the influence of the ringing-current is thus fore- In Fig. 2 a modification of the vibrating device is illustrated. It has two following arms 0 and 0 one on each side of the armature 1). They are insulated from one another, and the branch conductor 25 unites the conductor'qto the armo. There are two sets of separable contacts, oncnz, between the armaturep and arm 1 and the other, n", between the armature and arm 0 and in this arrangement both sets of contacts are in serial circuit with the magnet of the service-meter. Only when the cir c'uitthnough both sets of contacts is closed can an operative current pass through the coils of the saidginagnets. When the arm aturc is attractcd,it opens the contacts 72 and when it recedesfrom the magnet-poles it separates the contacts of at, so that when the magnet O is under the influence of such a vibratory current as that of the call-generator the circuit is practically opened continuously; but since the tendency of both arms is to follow the arluatu re and to contiuuall y reestablish the con-' tacts of both sets it-is manifest that whenthe apparatus is subjected to the inllucnceof a steady or unvarying current contact is sub stantially maintained, and this fact. insures the operation of the meter-magnet under'appropriate conditiops.

A third construction of my controlling de-- vice is shown in Fig. 3. It-consists of an electromagnet C and armature 11, as before; but the armature carries'at its lower extremity a small glass tube E, sealed at the ends by ecomlucting-plates and containing a number of metal particles ora globule of mcrcur the end contacts of the tube being connected in circuit, as shown. When the armature vibrates under the influence of an alternating or pulsating current, the particles of metal are thrown violently from one end of the tube to the other, thus keeping the circuit of the scolding-magnet open. When the tube is quiet, the particles of metal distribute themselves therealong, establishing a continuous contact from plate to plate. In the case of the mercury-globule it spreads out until it makes contact with both plates.

All of the several described forms of vibrator are obviously chased upon the same principle-viz. that of introducing a series of rapidly-recurring interruptions into the cir-f 8c cuit of the service-"meter magnet, while'alternating or pulsatory currents liable to produce undesired operationof that magnetare flowing in the said circuit, the apparatus produc-= ing such interruptions being at the same time maintained free from their influence by its position in the said circuit in series with a shunt-conductor arranged around the said service-meter magnet and the separable contacts at which thesaid interruptionsare proo duced.

I claim- 1. The combination at a telephone-station, witha telephone-circuit, and an electromag-T neticservice-meter connected therein, and 5 adapted to count the comniu.nications.initiatedat suchstation; of means responsive to the passage through said circuit, of alternating or vibratory electric currents, for producing interruptions in the circuit through the too actuating-electromagnet of said service-meter ;-whercby the said alternatingcurrents are prevented from affectingthe said meter, substantially as and for the purpose set forth.

2. The combination in a telephone system,

of a telephone circuit extending between a central station and asubstation; an electr magnetic call-counter or service-meter connected. with said circuit, and placed at the substation to register the calls thereof; and; no

an electromagnetic device therefor, control-' ling the continuity of the circuit throughthe electromagnet of said service-meter, and

, adapted to interrupt the same, on the passage through the circuit of alternating call-currents, but to maintain the same during the passage of steady currents; substautiallyas specified.

3. In a telephone-station apparatus, the

combination of a main circuit; a service-me 12o ter or call-counter having an actuating-electromagnet included in a branch thereof; a controlling device for preventing said meter from responding to alternating call-currents,

comprising'au electromagnet in saul main 011- :25

cuit, and a vibratory ci-rcuit-iuterrupter actuated by said magnet, but included in the service-meter branch of said circuit and adapted to produce rapid] y-recurrin g interruptions in the said branch while the said alternating r 0 call-currents are-iiowing in the main circuit, and to maintain substantial continuity thereof during the passage of steady currents; and asecond branch circuitor shunt around the said meter-magnet and interrupter, contain ing a resistance and maintaining the continuity ofvthe main circuit for the operation of said controlling-device magnet, independent of the said interrupter; as set forth.

4. In a telephone system, the combination in an electric circuit of the telephone-call register, and its controlling device, both at a substation with means as indicated for transmitting in such circuit alternating currents,

and direct currents of either direction; the

said controlling device being adapted to permit the operation of the said register by means of currents of the latter class, and to prevent its operation by currentstof the former class.

5. The combination in an exchange-telephone circuit between a central station and a substation; of means at the former station fonsending alternating or pulsating currents to the latterstatiou; a call-bell at the substationresponsive to said currents; and a permanently-shunted servicemeter in the circuit at the substation, the said meter being provided with an electromagnetic protective device operated by the said currents to intermittently open the circuit through said meter, leaving it closed through the shunt only; as set forth.

6; The combination in a telephone-circuit I extending between a central station and a substation, of a generator at the former station adapted to send alternating call-currents to the latter station; a call-bell at the substation responsive to said currents; a service-' meter having a sluggish actuating-electromagnet in the circuit at the substation; and an electromagnetic protective device operated by the said currents to open the circuit through the meter, at each alternation or' pulsation of said currents, and to thereby prevent the normal operation thereof,as set forth.

7. In a telephone system, the combination ofa telephone-circuit extending between a central station and a substation; an alternating-current call-generator associated therewith at said central station-for sending outgoing calls; a battery or steady-current generator also associated therewith at said cennating currents, but to maintain substantial continuity thereof on the passage of steady currents, an act-uating-electromagnet for the said interrupter in the main portion of the telephone-circuit; and a branch circuit containing a resistance-coil connected around the service-meter magnet and interrupter, to

maintain-an uninterrupted circuit for the main-line interrupter-magnet; substantially as specified.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses, this 4th day of January, 1900.

HERBERT E. snrtEEvE.

Witnesses:

GEo. WILLIS PIERCE, JosEPH A.-GATELY.

tral station to furnish a current-supplyfor 

